In UMTS, a plurality of transmission modes are provided. In Normal transmission mode, data bits representing transmitted information are sent from one antenna of a Node B in ordered temporal sequence. In Open Loop Transmit Diversity mode, data bits representing transmitted information are sent from two antennas of a Node B, and are sent in different temporal order from the two antennas. In Closed Loop Transmit Diversity modes 1 and 2, the data bits representing the transmitted information are sent in ordered temporal sequence from each of the two antennas of the Node B, but the bits are weighted differently for each antenna. The transmitted information is of a multitude of types, each having their special temporal reordering depending on the transmission mode.
At the receiving side. User Equipment (UE) has to handle all of the transmission modes for the different types information. This can be accomplished by implementing a plurality of reception paths, each adapted to take care of a certain type of information at a certain transmission mode. However, parallel processing paths will occupy more circuit area, consume more power, and increase costs. WO 01/06695 A1 discloses an example how pilot signals are received and handled for producing a channel estimate during an open loop transmit diversity mode. A problem with WO 01/06695 is that it cannot process more than the case when pilot symbols are present, and during open loop transmit diversity transmission mode. A multitude of solutions like the one disclosed in WO 01/06695, but for other transmission modes and channel types requiring other handling, has to be implemented in parallel in the UE. The requirements on the UE to be small and to have low power consumption are hard to meet in view of the multitude of reception paths, as cost requirements on the UE are considered. Different transmission modes for Frequency Division Duplex (FDD) transmission for Universal Mobile Telecommunication System (UMTS), Release 99 (R99), standard requires different processing for demodulation of a received signal. Parallel hardware processing paths for these different received signals for different modes require an extensive hardware implementation.